Differentiating large cell lymphoma from indolent small B-cell lymphoma infine needle aspirates using p53, PCNA and transformed lymphocyte count

OBJECTIVE: To determine the usefulness of proliferating cell nuclear antige n (PCNA), p53 protein expression and transformed lymphocyte count (TLC) as adjunctive rests to differentiate indolent small B-cell lymphoma from large cell lymphoma in fine needle aspiration biopsies. STUDY DESIGN: Aspirates of lymphoproliferative disorders from April 1993 to January i997 were reviewed. The percentage of TLCs tons determined all the Papanicolaou smear. The percentage and intensify of p53 and PCNA il immuno cytochemical staining was evaluated on cell block sections. These results w ere compared and correlated with the final diagnoses based on available mor phology, flow cytometry and clinical history. RESULTS: There were 40 cases of non-Hodgkin's lymphoma and 12 reactive lymp h nodes. Adequate cell blacks were available oil 16 large cell lymphomas, 7 grade 1-2 follicular center cell lymphomas, 6 mucosal associated lymphoid tissue lymphomas, 2 small lymphocytic lymphomas and 2 mantle cell lymphomas . Average TLC and p53 nuclear staining was highest in large cell lymphomas (57% TLC and 24% p53), followed by grades I and 2 follicular lymphomas (14% TLC and 15% p53) and lowest in other indolent lymphomas (<10% TLC and <1% p53). Average PCNA staining was highest in large cell lymphomas (46%) and l owest in small lymphocytic lymphomas (7%); however, TLC was the best parame ter for differentiating large cell lymphoma from indolent small B-cell lymp homa. CONCLUSION: TLC differentiated large cell lymphoma fi om indolent small B-c ell lymphoma better than either p53 or PCNA alone or in combination. Signif icant overlap between categories limits usefulness of these immunocytochemi cal stains for differentiating these entities.